1. Field of the Invention
The present invention relates to a method of employing a mixture of a cold-setting property comprising cement, bituminous emulsion and aggregate with impermeability and flexibility under a normal temperature constructing a continuous cut-off wall which can be utilized for stoppage of water leakage from foundation soil of a fill-type dam, such as an earth dam or a rock-fill dam, a cut-off for foundation soild of a levee, prevention of water permeation into a foundation soil of a dock and a cut-off in put excavation and shield works and the like.
Furthermore, this invention also relates to a method for constructing a core of shielding water for fill-type dams such as earth dams and rock-filled dams.
2. Description of the Prior Art
In recent years, a number of earth and rock-filled dams have been constructed. The dams had formerly been constructed on a bedrock excellent in shielding water, which is encountered after continuous excavation. However, the dams are lately driven by necessity to be constructed directly on an accretion layer of vast thickness which is highly permeable without removing the accretion layer for economical reasons.
As for the aforementioned case, there has been adopted "a certain grout method", so called, which impregnates cement milk and other chemical grouting into the ground through borings as a shielding method of water for the accretion layer, but it does not provide a continuous film of shielding water for certain.
A sheet pile method and an impregnation method have hitherto been put into practice for a cut-off for foundation soil of a levee, prevention of water permeation into foundation soil of a dock and a cut-off in pit excavation and shield works.
In the former case, it is difficult to perfect prevention of leakage from joints between sheets and, in the latter case, it is very expensive. For overcoming these disadvantages, there is a method for constructing a continuous cut-off wall by filling a cement concrete into a pit of wall-shaped excavation in the ground, in which the continuous cut-off wall is too hard to follow distortion of a foundation soil and apt to be cracked without a satisfactory result of effecting the cut-off.
Under the circumstances as mentioned above, there has been a method of constructing a cut-off wall wherein a hot asphalt mixture of heat-mixing asphalt and aggregate such as asphalt concrete, and Gussasphalt or mastic asphalt is grouted. However, when a pit of a wall shape is excavated in the ground and is used with mud water of bentonite in order to prevent a collapse of a foundation soil, the hot asphalt mixture has been hard in executing works and apt to be set by being cooled with water during grouting, and to cause spaces with the water being boiled, thereby accompanying drawbacks of difficult quality control and danger. Therefore, it has been demanded to develop a method of obtaining and constructing a material which is placed at a normal temperature as in the case of the conventional cement concrete and provides a flexibility and impermeability, as in the case of the hot asphalt mixture, offering a uniform quality.
A core material for a fill-type dam has been formed of compaction of natural soil such as clay or heated asphalt concrete. In recent years, the application of the asphalt concrete has been increased since clay of good quality became hard to obtain, the execution of works is apt to be influenced by weather and the endurance for earthquake is troublesome. However, the asphalt concrete has necessitated an asphalt concrete plant for heating which requires large scale equipment and decreased efficiency since the height of one execution of works has been only some 10 cm, due to the rolling compaction required for the asphalt concrete.